Rotary hook for sewing machines



Sept. 30, 1947. M, Q IVANDlCK 2,428,027

ROTARY HOOK FOR SEWING MACHINES Filed July 22, 1944' llg In HMM!! Patented Sept. 30, 1947 ROTARY HQQK FOR SEWING MACHINES Matthew G. rvandick, Rockford, 111;, assigner to',

Free Sewing Machine Co., Rock-forilvll., a co1'.-

poration of Illinois ApplicationJuly- 22, 1944, Serial No.r546;169l

3 Claims. 1v

This invention relates to a new and; improved rotary hook forsewing machines, and hasv for its principalobject the provision of simple andl practical means. for luloricationof the bobbin case,` rib and theracewaytherefor.,whereby adequate lubrication is insured; over long; periods of operation, withoutneed :for replenishing the supply of lubricant, andv withontdanger of contamination of the threadwithoil.,

The; improvements ,of mfyinvention, more specifically stated are anplieditoa rotary hook constructed along. the.1 lines; ofY that disclosed in the Southam and Wainwright Patent 2,065,349, a yieldable o r loatinggib; ring of improved design being provided in, connection with, the beveled ribpnthebObbincaSe base tovforma raceway for the rib andv alsoform; a container for a circumferentially extending lubricant retaining Wick, which provides suilicientstorage capacity for oil A without danger of excessive lubrication, the bulk ofthe lubricant` being. kept away from contact with the bobbinjcase rib and thel raceway therefor by centrifugal action in" the rotation of the thread-'loop carrier, although the wick is close' enough to' the raceway'to' insure` adequate lubrication more or` less by capillary attraction.

In the structure of the Southam and'A Wainwright'patent,` a'plurali-ty of' screws are employed to' 'fasten 'the gib-ring' to the thread-loop; carrier; andv compress-a1nunrber of coiled compressi-onV springs for# yieldabil-ityoff the ring-,'- so as to eliminate likelihood 'of binding-but i-nV accordance with-my-inventienfprovide-aplurality of spring clips, inserted--between-'lugs on theV back ofl the ring. and thel loa-cle off arrVv annular flange on the threadflbepearrier; v-wlliereby to 'ins-ure more uniform. spring actionand-at thesameltime simplify theconstruction,make it-easier to assemble, and lower the. cost all around. I

Y The invention is illustratedin the accompany-- ing drawing, in Whicl1 Figi. is arfacevieweoff'a rotar-y hook, embodying my invention;` f

t F'igY 2;. is: a cross-section. on the line 2-2' of Fig. 1;.` Y

Fig.,31isarear view'of the-rotaryfhook; .t

Eig. .4Sisa side view, and; f

Figs. 5y and Snare enlarged sec-tional.` details on the correspondingly numbered and 4, respectively.

The same reference :numerals are applied tol correspondingvparts throughout' these-views..

'Ehe-rotary hoolc'fshown islclosely similar to that. discl'osediin the Southam and Wainwright pat.-

y ent mentioned aboveand: comprises a threadw lines of Figs.. 3,.

, 2 loop carri-er I0-support-ing; for relative rotation a bobbiniease base `I Imllhich `in turn rotatiyely supportsabobbin lf2; retainedgin the Ibase by a case I3; Ahob Uly providesra means for securing the carrier i0 tio the vdrivingshaft. of; a sewingmachinevand nasa bowl shaped portion I5 integral therewith andterminating. in an annular flange or rim portion I6; ReceivedI partially vwithin the bowl shaped portion |15 isI the bobbincasebase Il, which is generallyA cylindrical; and formed intermediate its ends` with at c ircnmferentially extending rib I1. thatris received in an annular groove I8 for-med inthe inner rim portion of. vthe bowl shaped p or-y tion- I5, A- gibring I9? adapted to be secured to the-,flange I Iii serves to= retain the bobbin case base inthebowlshaped portion I5 while forming with theggroove I8y a nacewayforthe rib I1. At 20is.

indicated a spring clip.` secured to the bobbin case i3` by; means of, anscrew Zlrand cooperating with a tongue-,2.2; extending radially from the ease I3 to support;thebobbinthread inposition adjacent the path; of; the sewing; machine'needle in addition tov maintaining; zt-he" proper tension on the bobbirr thread; A1 loop piercing; hook 23 is pro-A Vid'ed'onJ theirimof; the bowls'halped portion I5; of. the thread-loQIl-carrer andprojects forwardly in the ,directionoff rotation ofthe carrier and outwardly from the. carrier beyondv the plane of the dance. lr6 to ,engage the tnreadelcop on the Sewing machine needle and; loop it around the bobbin thread in the usual way, to form a sti-tch. No invention-lisclaimed-inany of the details thus far described, excepting` onlyl insofar as such details form a. part of. novel combinations in, accordance with; the present invention, as pointed out generally above, and asfmore specifically described hereinafter.,

,Inaccordance-witmmy invention, the gib ring. I9 isformedl to providefan annular radially inwardlvjproiecting flange 24: for abutment, with thefouter face of therib I1, and to completethe racewaytherefznsarid angeand the rest of that section o-f-k the ring beingcut away, as indicated at 25.-, where the hook 23 -i-sprovided von the thread-loopl carrier, so as to permit projection of said hook past the plane of the ring forproper cooperation with. the needle `o f. the machine. The

ring I9 is cut awayat 2,5 tlirouglnl approximately Soiasrequiredpfor theproper functioning of the hook ,23.-V Radially outwardlyfwith respect to the annular ange 24,. theA ring. la is formed. to provide anannular: ch'annelor recess 2,6V to receive.

' a lubricant, retainingwick. 2J throughout approxi-mately 270 anglllarityof thering I9'. The web 84 ofgthe, channel recess has an' opening 29;

provided therein, so as to permit easily oiling the device without having to take it apart, that is to say, by entry of the nozzle of an oil can in the opening 29. The wick 21 will readily absorb the oil supplied in this manner, and there is, therefore, no danger of oil being left on the outside of the ring I9, or running onto the outside, assuming reasonable 'care and v'judgment is' exercised in the lubrication of the machine. The opening 29, as indicated in Fig. 1, is preferably near the leading end of the channel 26 in relation to the direction of rotation of the threadloop carrier indicated by the arrow in Fig. 1, so that there is less likelihood of anyoil finding its way out of the opening 29 under centrifugal action, the bulk of the oil tending to crowd toward the other end of the recess 26, as a result of the inertia factor. sure keeping the bulk of the lubricant away from contact with the rib I'I and the raceway therefor in the rotation of the'thread-loop carrier, but lubricant will find itsway to the rib and raceway in sufficient amounts moreorless by capillary attraction to insure vsufficient lubrication. Since the lubrication is done so sparingly, it is obvious that the machine can be run for long periods without requiring oiling, and there is not much danger of contamination of the thread with oil in the operation'of thermachine. Capillary attraction can be relied upon in` this case,because of two things: (1) the ring I9 is yieldably secured to the thread-loop carrier, as hereinafter described, and, therefore, v'does not engage the annular face 30, next to the groove I8, too tightly; and, (2) the Vwiclc 2'l isin contactvwth, and therefore wets, the radially outer portion of the face 3U, and there is only arrelatively narrow portion of the face 'between thewetted,` portion and the groove I8 tov be traversed by the oil bycapillary attraction, as clearly appears in Fig. 2. The provision of the correct amount yofslubricant is highly important in this portion of the machine, because of the speed of rotation,and the'more or less continuous operation wheneverthe ma` chine is used. Absolute freedom-ofimovementis highly vimportant, from -the standpoint of i stitch formation, and to avoidlikelihood-v of# thread breakage, On the other'hand; ifi there is not sufficient lubricatiomthe rib CII and its lraceway are apt to become `'worn excessively, and when that occurs, there is no :longer obtainable'the desired smoothness ofoperation, andthe thread orlint and dirt are apt'to become lodged between the relatively rotating parts and cause jamming. With the present;` constructiori'f all i of these o diniculties are avoided by reason of the fact that there is adequate storage capacity for oilinlthe channel 26 Vfor operation overa long period of time, and-the lubricant cannot be wasted by beingthrownf outwardly under centrifugal force, centrifugal force being relied upon in accordance with the present invention to retain lubricant so that it will be used only very sparingly and capillary attractionV being relied upon to carry the lubricant toV the parts requiring it, -as previously described. A f l 'i y The nange I6, which 'is on the thread loop carrier, hasa plurality of circumferentially spaced transverse Y grooves cut' therein, as indicated at 3|, oneor moreof whichare adapted to receive indented key portionsv 32, formed in the peripheral wall 33 of the ring I9. The latter'ts closely over the periphery of the flange I6 as clearly appears in Figs, 2 and 6, both to Iriaintainaccurate concentricity of the `ring I9 with' respect to the thread carrier I0, and also avoid likelihood of oil seepage through this joint in the operation of the machine. There are three lugs 34 on the back of the ring I9, projecting radially inwardly from the inner edge of the wall 33 in register with the notches or grooves 3l, so that the ring I9 ,can be assembled orwdisassembled easily by passage of these lugs through fthese grooves. These lugs cooperate with :springclips 35, which are inserted between the lugs 34 and the back of the flange IE to hold the ring I9 in assembled Y relation to the thread-loop carrier I0, and at the Centrifugal force V,will

` same time provide the desired yield for the ring I9 in relation to the thread-loop carrier to allow enough lateral movement to prevent binding in the operation of the machine. The key projection 32 locks the ring I9 against turning with respeci; to the thread-loop carrier IIl', and keeps the cutout portion 25 of the ring in proper relation to the hook 23 on the carrier. The spring clips 35 are generally M-shaped, as best appears in Figs. 4 and 5, whereby to provide two legs 36 for abutment with the back of the flange I6, a middle portion 31' for abutment with the lugs 34 on the ring I9, and humps 38 on opposite ends of the middle portion to engage the opposite sides of the lugs 34 to prevent accidental displacement of the clips from their assembled positions. These clips are in equally circumferentially spaced relation as shown .in'Fig-.` 3 and each has sufficient spread so that `the spring tension on the ring I9 is substantially uniform throughout its circumference. Furthermore, these clips can be easily inserted in less time than is required to insertI a similar number ofsmall screws, especially when the screws have to be entered through coiled compression springs as ldisclosed in the Southarn and Wainwright patent. A saving in time and expense is therefore frealized, Vand the overall cost of the unit is reduced.

It is believed the foregoing de'scription conveys a good understanding'of the 'objects 'and advantagesV of my invention. ,The 'appended claims have been drawn'with'a view to` covering all legitimatemodifications andfadaptations.

Iclaim:

l. In a rotary hook Vfor-sowing machines, a rotary thread-loop carrier having aloop piercing hook, a bobbin case beschaving ,a circumf ferential rib, a gib ringV disposed on thel outside of said carrier and forming `therewith a raceway for the rib onsaid base, saidzcarrierhaving an annular fiange andgsaidring having an annular rim portion having ajclose Working fit over the peripheryof saidangeto center the ring on the carrier and guidewsaidring fory lateral movement thereon, saidiiange having notches provided across the periphery,l thereofr at circumferentially spaced pointssaid ring-having a pl1 rality of circumferentiaHypaced radially inwardly projecting lugs registering with, said notches and movable therethrough` in the assembling of the ring on the carrier and disposed in spaced relation to the back of said flange,l and spring means disposed between said lugs and the back of said flange forfyieldably mounting 'the gib ring on said .carrier for limited lateral yInovement. 1" f' 2. A structure as set forth injolaim 1, wherein said ring has at leastA one `key projection on the rim portion thereof projecting .radially inwardly, adapted to enter one of the .aforesaidnotches in said, flange to key the ringtothecarrierso as to prevent relative rotation therebetween. .L

3. In a rotary hook for sewing machines, a rotary thread-loop carrier having a radial liange on its periphery, the front face of which is ,fiat and smooth and is recessed at its inner circumference to provide a beveled seat, a bobbin case base having a circumferential rib the outer face of which is flat and disposed in the piane of the at front face of said flange and the other face of which is inclined at the same angle as the Ibeveled seat and has bearing engagement therewith, a gib ring having a smooth surfaced flat annular portion abutting the front face of said flange and the front face of said rib to retain the bobbin case base in said carrier, said ring having an annular recess provided therein in the radially outer portion thereof containing a lubricant retaining Wick disposed so as to permit lubrication by capillary attraction of the rib and the surfaces on the carrier and ring contacted thereby,

and means for resiliently securing the gib ring to said carrier.

MATTHEW Gr. IVANDICK.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 10 Number Name Date 2,295,511 Barron Sept. 8, 1942 2,101,329 Eames et al Dec. '7, 1937 2,219,388 Hansen et al Oct. 29, 1940 1,456,082 Warren May 22, 1923 15 2,163,899 Fleckenstein et al. Dec. 28, 1937 FOREIGN PATENTS Number Country Date 519,866 Germany Mar. 5, 1931 

